1. Technical Field
The present invention relates to a method and apparatus for painting parts, and more particularly to a method and apparatus for repetitively and automatically mating parts with shields and painting the unshielded surfaces of the parts.
2. Background Art
Paint systems are known in the art in which shields are mated with parts to shield certain surfaces so that only selected surfaces of the part are painted by a paint spray. Such systems are typically used in large volume industries such as the automotive industry where it is necessary to paint thousands and even millions of the same part (e.g. tail lights or grills).
Shields which are used in such painting operations can cost from $2,000 to $5,000 each depending upon the part being painted. Shields naturally get paint on them during the painting process and therefore it is required that the shields be changed occasionally for cleaning the paint therefrom. As a result, 8-10 shields are typically required for each system. Further, since the system must be stopped while the shields are changed, the down time resulting from shield changing causes a substantial reduction in productivity for the system. Changing shields also requires that the shields be handled, and inevitably the shields are mishandled and damaged, resulting in significant costs for shield maintenance.
Since painting in the prior art systems is accomplished by using a paint spray, the parts have necessarily been placed in closed areas or booths during painting. Paint of course gets on the walls of the booths, which must necessarily also be cleaned, again resulting in down time (typically 10% of operating time) and decreased productivity. Further, the booths of the prior art systems generally have required pits beneath them within which waste from the painting process is received. As a result, the booths are difficult to install and require that floor space (normally 500 square feet per booth) be dedicated for the booth.
Further, the painting systems of the prior art are generally operator controlled, which allows the operator to work at his own pace. Studies have shown that this most often results in less than maximum productivity from an operator.
Further, in some prior art paint systems, the operator is located in the booth during painting and safety and health standards require that large amounts of air be moved through the booth (e.g. 10,000 cubic feet per minute). Such a large air flow results in substantial heating costs in cold climates. Further, in order to provide for such air flow, a large initial capital outlay is usually required for the equipment capable of moving and heating that amount of air, and large operating expenses, particularly energy costs, are incurred in running that equipment.
The present invention is directed toward overcoming one or more of the problems as set forth above.